+PH/26 Change scripts/os-type so that when "uname -s" returns just "GNU", the
+ answer is "GNU", and only if the return is "GNU/something" is the answer
+ "Linux".
+
+PH/27 $acl_verify_message is now set immediately after the failure of a
+ verification in an ACL, and so is available in subsequent modifiers. In
+ particular, the message can be preserved by coding like this:
+
+ warn !verify = sender
+ set acl_m0 = $acl_verify_message
+
+ Previously, $acl_verify_message was set only while expanding "message"
+ and "log_message" when a very denied access.
+